Illumination apparatus for a motor vehicle

Abstract

The invention relates to an illumination apparatus ( 100 ), in particular for a motor vehicle, comprising at least one laser light source ( 10 ) for producing excitation light, at least one wavelength conversion element ( 20 ), which is designed to receive excitation light from the at least one laser light source ( 10 ) in the form of an excitation-light light bundle, at least one optical imaging element ( 30 a, 30 b, 30 c; 31; 32 ), which images light, which is emitted in the visible wavelength range by the wavelength conversion element ( 20 ), in the form of at least one light distribution or one partial light distribution (LVa, LVb, LVc, LVd, LVe), and at least one beam-deflecting device in the beam path between the at least one laser light source ( 10 ) and the at least one wavelength conversion element ( 20 ). The beam-deflecting device is designed as an acousto-optic modulator ( 40 ), which comprises a solid medium ( 40 a ), which is optically transparent at least to excitation light of the at least one laser light source ( 10 ) and through which the excitation-light light bundle is passed, and wherein a control device ( 41 ) is provided, by means of which sound waves having a frequency or a plurality of, in particular, different frequencies can be produced in the solid medium ( 40 a ) of the acousto-optic modulator ( 40 ) in accordance with specified or specifiable control parameters such that the excitation-light light bundle is deflected to different regions ( 20 a, 20 b, 20 c; 20 a, 20 b, 20 c, 20 d, 20 e ) of a conversion element ( 20 ) and/or to different conversion elements in accordance with the frequency of the applied sound waves.

The invention claimed is: 
     
       1. An illumination apparatus ( 100 ) for a motor vehicle, comprising:
 at least one laser light source ( 10 ) configured to produce excitation light; 
 at least one wavelength conversion element ( 20 ), which is designed to receive the excitation light from the at least one laser light source ( 10 ) in the form of an excitation-light light bundle; 
 at least one optical imaging element ( 30   a ,  30   b ,  30   c ;  31 ;  32 ), which is configured to image light, which is emitted in the visible wavelength range by the at least one wavelength conversion element ( 20 ), in the form of at least one light distribution or one partial light distribution (LVa, LVb, LVc, LVd, LVe); and 
 at least one beam-deflecting device in the beam path between the at least one laser light source ( 10 ) and the at least one wavelength conversion element ( 20 ), 
 wherein the at least one beam-deflecting device is designed as an acousto-optic modulator ( 40 ), which comprises a solid medium ( 40   a ), which is optically transparent at least to the excitation light of the at least one laser light source ( 10 ) and through which the excitation-light light bundle is configured to be passed, 
 wherein sound waves having a frequency, or a plurality of different frequencies, are configured to be produced in the solid medium ( 40   a ) of the acousto-optic modulator ( 40 ) such that the excitation-light light bundle is deflected to different regions ( 20   a ,  20   b ,  20   c ;  20   a ,  20   b ,  20   c ,  20   d ,  20   e ) of a conversion element ( 20 ) and/or to different conversion elements in accordance with the frequency of the applied sound waves, and 
 wherein an optical deflecting device ( 50 ) is arranged between the at least one conversion element ( 20 ) and the at least one acousto-optic modulator ( 40 ), which deflecting device is configured to deflect the excitation light, exiting from the at least one acousto-optic modulator ( 40 ) or the acousto-optic modulator arranged closest to the conversion element ( 20 ), parallel to a basic diffraction direction or normal to an application plane of the conversion element ( 20 ) on which the excitation light is incident. 
 
     
     
       2. The illumination apparatus according to  claim 1 , wherein a second acousto-optic modulator is arranged between a first acousto-optic modulator and the at least one wavelength conversion element, the solid medium of said second acousto-optic modulator being configured to be passed through by the excitation light exiting from the first acousto-optic modulator, and wherein the second and the first acousto-optic modulator are arranged relative to one another in such a way that the direction of propagation of the sound waves in the two acousto-optic modulators are orthogonal to one another. 
     
     
       3. The illumination apparatus according to  claim 1 , wherein the frequency of the sound waves applied to the at least one acousto-optic modulator ( 40 ) is varied over time by a control device ( 41 ) that is designed to vary the frequency of the sound waves over time. 
     
     
       4. The illumination apparatus according to  claim 1 , wherein the produced sound waves are flat waves (SW). 
     
     
       5. The illumination apparatus according to  claim 1 , wherein the at least one acousto-optic modulator ( 40 ) is configured to be operated in the Bragg regime. 
     
     
       6. The illumination apparatus according to  claim 5 , wherein for deflection of the excitation-light light bundle from a basic position on the conversion element, the basic frequency f 0  corresponding to this basic position is varied by a value of +Δf. 
     
     
       7. The illumination apparatus according to  claim 6 , wherein the frequency change occurs continuously or in steps. 
     
     
       8. The illumination apparatus according to  claim 1 , wherein the frequencies of the sound waves lie in a range of from 80 to 2500 MHz. 
     
     
       9. The illumination apparatus according to  claim 1 , wherein exactly one optical imaging element ( 31 ,  32 ) is provided or exactly one optical imaging element ( 31 ,  32 ) for each conversion element ( 20 ) is provided. 
     
     
       10. The illumination apparatus according to  claim 1 , wherein exactly one optical imaging element ( 30   a ,  30   b ,  30   c ) is provided for each region ( 20   a ,  20   b ,  20   c ) of a conversion element ( 20 ) in which excitation light can be deflected. 
     
     
       11. The illumination apparatus according to  claim 1 , wherein one or more optical imaging elements ( 30   a ,  30   b ,  30   c ;  31 ) is/are designed as a reflector or reflectors. 
     
     
       12. The illumination apparatus according to  claim 1 , wherein one or more optical imaging elements ( 32 ) is/are formed as a lens or from lenses. 
     
     
       13. The illumination apparatus according to  claim 1 , wherein the deflecting device ( 50 ) comprises or consists of a lens arrangement for a telecentric objective. 
     
     
       14. The illumination apparatus according to  claim 1 , wherein the illumination apparatus is installed in a motor vehicle, and the control parameters at a defined moment in time are dependent on a state of the motor vehicle at this defined moment in time or are dependent on a state of the motor vehicle within a time period around this defined moment in time. 
     
     
       15. The illumination apparatus according to  claim 1 , wherein the produced light distribution or partial light distribution can be displaced in the horizontal and/or vertical direction. 
     
     
       16. The illumination apparatus according to  claim 1 , wherein the produced partial light distribution forms part of a main beam distribution. 
     
     
       17. The illumination apparatus of  claim 16 , wherein the produced partial light distribution forms part of a central, maximum spot of the main beam distribution. 
     
     
       18. The illumination apparatus according to  claim 1 , wherein the sound waves have an angle of aperture δθ S  in the solid medium ( 40   a ), wherein δθ S ≥Δθ, and wherein Δθ is the maximum angle of deflection of the laser beam from a basic diffraction direction. 
     
     
       19. The illumination apparatus according to  claim 18 , wherein the sound waves are flat sound waves. 
     
     
       20. The illumination apparatus according to  claim 1 , wherein the direction of propagation of the sound waves, in particular of flat sound waves, can be changed, wherein the direction of propagation can be changed according to the frequency of the sound waves or the change in frequency of the sound waves. 
     
     
       21. An illumination system comprising two or more illumination apparatuses according to  claim 1 , wherein each of the illumination apparatuses is configured to form a partial light distribution, which partial light distributions are arranged side by side and/or one above the other, with neighbouring and/or adjacent partial light distributions overlapping one another in part. 
     
     
       22. A motor vehicle headlamp having one or more illumination apparatuses according to  claim 1 . 
     
     
       23. The illumination apparatus of  claim 1 , wherein the sound waves having a frequency, or a plurality of different frequencies, are configured to be produced in the solid medium ( 40   a ) of the acousto-optic modulator ( 40 ) by means of a control device ( 41 ), which controls the at least one acousto-optic modulator ( 40 ) in accordance with specified or specifiable control parameters. 
     
     
       24. The illumination apparatus according to  claim 1 , An illumination apparatus ( 100 ) for a motor vehicle, comprising:
 at least one laser light source ( 10 ) configured to produce excitation light; 
 at least one wavelength conversion element ( 20 ), which is designed to receive the excitation light from the at least one laser light source ( 10 ) in the form of an excitation-light light bundle; 
 at least one optical imaging element ( 30   a ,  30   b ,  30   c ;  31 ;  32 ), which is configured to image light, which is emitted in the visible wavelength range by the at least one wavelength conversion element ( 20 ), in the form of at least one light distribution or one partial light distribution (LVa, LVb, LVc, LVd, LVe); and 
 at least one beam-deflecting device in the beam path between the at least one laser light source ( 10 ) and the at least one wavelength conversion element ( 20 ), 
 wherein the at least one beam-deflecting device is designed as an acousto-optic modulator ( 40 ), which comprises a solid medium ( 40   a ), which is optically transparent at least to the excitation light of the at least one laser light source ( 10 ) and through which the excitation-light light bundle is configured to be passed, 
 wherein sound waves having a frequency, or a plurality of different frequencies, are configured to be produced in the solid medium ( 40   a ) of the acousto-optic modulator ( 40 ) such that the excitation-light light bundle is deflected to different regions ( 20   a ,  20   b ,  20   c ,  20   a ,  20   b ,  20   c ,  20   d ,  20   e ) of a conversion element ( 20 ) and/or to different conversion elements in accordance with the frequency of the applied sound waves, and 
 wherein an optical deflecting device ( 50 ) is arranged between the at least one conversion element ( 20 ) and the at least one acousto-optic modulator ( 40 ), which deflecting device is configured to deflect the excitation light, exiting from the at least one acousto-optic modulator ( 40 ) or the acousto-optic modulator arranged closest to the conversion element ( 20 ), in such a way that laser light spots of equal size are produced on a planar conversion element regardless of the angle of deflection. 
 
     
     
       25. The illumination apparatus according to  claim 24 , wherein the deflecting device ( 50 ) comprises an f-theta lens or an f-theta lens arrangement or a lens arrangement that comprises or consists of at least one f-theta lens.